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Go back to opening screen 9 Chapter 2 Physical/Geographical Characteristics of the ––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––

Contents 2.2.1. Climate boundaries 2.1. Introduction ...... 9 On the basis of temperature, the Arctic is defined as the area 2.2. Definitions of the Arctic ...... 9 2.2.1. Climate boundaries ...... 9 of the 10°C July isotherm, i.e., north of the region 2.2.2. Vegetation boundaries ...... 9 which has a mean July temperature of 10°C (Figure 2·1) 2.2.3. Marine boundary ...... 10 (Linell and Tedrow 1981, Stonehouse 1989, Woo and Gre- 2.2.4. Geographical coverage of the AMAP assessment ...... 10 gor 1992). This isotherm encloses the Arctic , Green- 2.3. Climate and ...... 10 2.3.1. Climate ...... 10 land, , most of and the northern coasts and 2.3.2. Atmospheric circulation ...... 11 islands of , and (Stonehouse 1989, 2.3.3. Meteorological conditions ...... 11 European Climate Support Network and National Meteoro- 2.3.3.1. Air temperature ...... 11 2.3.3.2. Ocean temperature ...... 12 logical Services 1995). In the west of Nor- 2.3.3.3. Precipitation ...... 12 way, the heat transport of the North Atlantic Current (Gulf 2.3.3.4. Cloud cover ...... 13 Stream extension) deflects this isotherm northward so that 2.3.3.5. Fog ...... 13 2.3.3.6. Wind ...... 13 only the northernmost parts of are included. 2.4. Physical/geographical description of the terrestrial Arctic 13 Cold water and air from the Basin in turn 2.4.1. General geographical description ...... 13 push the 10°C isotherm southward in the region of North 2.4.2. and physiography ...... 15 America and northeast , taking in northeastern Labra- 2.4.3. Permafrost and soils ...... 16 dor, northern , , central Kamchatka, and 2.5. Arctic freshwater environments ...... 17 2.5.1. Rainfall and snow ...... 17 much of the Bering (Stonehouse 1989). 2.5.2. Groundwater ...... 17 Another geographical indicator of the Arctic region that is 2.5.3. Wetlands ...... 17 2.5.3.1. Lowland polygon bogs and fens ...... 17 partially determined by climate is the presence of permafrost 2.5.3.2. Peat mound bogs ...... 18 (Barry and Ives 1974). The southern boundary of continu- 2.5.3.3. Snowpatch fens ...... 18 ous permafrost is shown in Figure 2·11. 2.5.3.4. pool shallow waters ...... 18 2.5.3.5. Floodplain marshes ...... 18 2.5.3.6. Floodplain swamps ...... 18 2.5.3.7. Wetland occurrence ...... 18 2.5.4. Rivers ...... 18 2.5.5. Lakes ...... 19 2.5.6. Estuaries ...... 20 2.6. Arctic marine environment...... 20 2.6.1. Geographical area and bathymetry ...... 20 2.6.2. Hydrographic conditions in the Arctic ...... 21 2.6.3. Ocean currents ...... 23 2.6.4. Sea ice ...... 23 Acknowledgments ...... 23 References ...... 23

2.1. Introduction The vast region of the Arctic extends across northern , northern and northern Asia, taking in eight countries and the expanses of sea and ocean in between. The terrestrial, freshwater and marine environments throughout this area exhibit considerable variation in climate, meteoro- logy and physical . This chapter describes this di- versity as a background to discussions on contaminants and AMAP area other stressors in these environments. Arctic marine boundary 2.2. Definitions of the Arctic region 10 C July isotherm Figure 2·1. The Arctic as defined by temperature (after Stonehouse 1989), The Arctic is often delimited by the Arctic Circle (66°32'N) and the Arctic marine boundary, also showing the boundary of the AMAP (Figure 2·1), which approximates the southern boundary of the assessment area. sun. Such a definition, however, is simplistic, given variations in temperature, presence of mountain ranges, distri- 2.2.2. Vegetation boundaries bution of large bodies of water, and differences in permafrost occurrence. Outlined below are some definitions of the Arctic A floristic boundary used to delimit the terrestrial Arctic is region which take into account physical, geographical and/or the treeline (Figure 2·2) (Linell and Tedrow 1981). Simply ecological characteristics. Following these, the Arctic region, as defined, the treeline is the northern limit beyond which trees defined for the purposes of the AMAP assessment, is discussed. do not grow. More accurately, it is a transition zone between 10 AMAP Assessment Report

76°N. Warm Pacific water passing through the meets the Arctic Ocean water at approximately 72°N, from in the west to Amundsen Gulf in the east (Stonehouse 1989). However, once it passes through the Bering Strait, Pacific water begins to undergo modification on the broad Chukchi shelf due to ice-related processes (freezing, melting, cooling) and the addition of runoff. Modified water becomes incorporated into the surface mixed layer or subducts and flows down the undersea can- yons to contribute to the halocline. Recognizing the diffi- culty of assigning a distinct boundary separating Pacific water from Arctic water, the boundary is arbitrarily drawn across Bering Strait as the point at which modification is likely to commence. Similarly, for the purposes of the AMAP assessment, and recognizing other factors which may be used to define the Arctic marine area, such as Arctic marine biology and sea ice cover, the AMAP marine area to the south of the region as defined above also includes: , the and Hudson Bay; the , Iceland, Norwegian, Barents, Kara and White ; and the .

2.2.4. Geographical coverage High Arctic Subarctic of the AMAP assessment Low Arctic Treeline Given the different definitions of the Arctic, based on phys- Figure 2·2. Arctic and subarctic floristic boundaries (Bliss 1981, Linell and ical-geographical characteristics as described above, and Tedrow 1981, Nordic Council of Ministers 1996). those based on political and administrative considerations within different countries, no simple delineation of the Arc- continuous boreal forest and tundra, with isolated stands of tic region was applicable for the purposes of the AMAP as- trees. In North America, the tundra-forest boundary is a nar- sessment. To establish a geographical context for the AMAP row band, but in this region can be up to 300 km assessment, therefore, a regional extent was defined based wide (Stonehouse 1989). It corresponds with the climatic on a compromise among various definitions. This incorpo- zone where the Arctic air masses meet the air masses orig- rates elements of the Arctic Circle, political boundaries, veg- inating from the south over the subarctic (Bryson 1966 in etation boundaries, permafrost limits, and major oceano- Larsen 1973). graphic features. The region covered by AMAP is, therefore, The treeline roughly coincides with the 10°C July iso- essentially the terrestrial and marine areas north of the Arc- therm (Stonehouse 1989, Woo and Gregor 1992). How- tic Circle (66°32'N), and north of 62°N in Asia and 60°N in ever, in some areas, the treeline lies 100-200 km south of North America, modified to include the marine areas north the isotherm, adding western Alaska and the western Aleu- of the Aleutian chain, Hudson Bay, and parts of the North tians to the Arctic region (Stonehouse 1989). Atlantic Ocean including the Labrador Sea. The Arctic region is often divided by ecologists into the As stated above, the AMAP boundary was established High Arctic and the Low Arctic as shown in Figure 2·2 to provide a geographical context for the assessment, in and described in chapter 4, section 4.4.1. South of the particular source-related assessment issues, i.e., considera- Arctic is the subarctic, the region lying between the closed- tion of sources within and outside the Arctic. The relevance canopy boreal forests to the south and the treeline to the of the AMAP boundary (Figure 2·1) varies when consider- north (Figure 2·2). This region, which combines character- ing different issues, and it has therefore been applied ac- istics of both the boreal forest and the Arctic tundra, is cordingly. Thus, contaminant levels in biota are addressed also referred to as the or forest tundra. The southern in relation to the geographical occurrence of the species boundary of the subarctic generally corresponds with the concerned; demographic data are discussed in relation to southern limits of discontinuous and sporadic permafrost. administrative on which, for example, census data Thus, permafrost is present throughout most of the sub- are collected. arctic (Linell and Tedrow 1981).

2.2.3. Marine boundary 2.3. Climate and meteorology 2.3.1. Climate Based on oceanographic characteristics, the marine bound- ary of the Arctic is situated along the convergence of cool, The polar areas are characterized by low air temperatures. less saline surface waters from the Arctic Ocean and warm- This is because they receive, on an annual basis, less solar er, saltier waters from to the south (Figure 2·1). In radiation than other parts of the world. However, the radia- the eastern Canadian , this zone exists tion levels vary greatly depending on the . In the win- approximately along a latitude of 63°N, and swings north ter months, there is a total lack of incoming solar radiation, between Baffin Island and the west coast of Greenland. Off while in the , the poles receive higher levels of solar the east coast of Greenland, the marine boundary lies at ap- radiation than any other place on . proximately 65°N. The warming effect of the North Atlan- The annual amount of solar radiation received is less than tic Current deflects this boundary north of 80°N west of that which is lost to space by long-wave radiation, since a , while it moves southward in the to large part of the solar radiation that reaches the Earth is re- Chapter 2 · Physical/Geographical Characteristics of the Arctic 11

flected by extensive cloud, snow and ice cover. This radia- 2.3.2. Atmospheric circulation tion imbalance produces low temperatures and results in a redistribution of heat from southern latitudes via air and The pattern of mean sea-level pressure for January in the ocean currents (Varjo and Tietze 1987). This energy regime Arctic shows a low-pressure area over the North Atlantic is the fundamental factor driving the Arctic climate. Ocean around southern Greenland and Iceland (Icelandic The effect of macro-scale topography of the Earth’s sur- Low) and a low-pressure area over the Pacific Ocean south face, in particular the distribution of land, sea and moun- of the Aleutians (Aleutian Low) (Figure 2·3). The influence tains, is important for regional and local climatic conditions of the Icelandic Low extends to the , while that in the Arctic. The frequency and the preferred tracks of the of the Aleutian Low is effectively blocked by the mountains persistent Pacific and Atlantic low-pressure systems and the of Alaska and northeast (Barry and Hare 1974). The position of the persistent high-pressure systems not only large-scale air circulation over the North Atlantic Ocean is play an important role in the existence of the regional and determined by the Icelandic Low and the high-pressure areas local climates in the Arctic, but also link the Arctic climatic over Greenland and the Central Arctic Basin. The prevailing system to the world climatic system. winds are westerly or southwesterly between Iceland and Scandinavia, transporting warm and humid air from lower 1000 latitudes toward the Arctic. Farther north, the circulation is Aleutian Low generally anticyclonic around the pole with easterly and northeasterly prevailing winds. Strong winds over large 1004 areas are associated with intense depressions. These winds 1008 1012 are most frequent in the Atlantic sector of the Arctic where 1016 they follow a track from Iceland to the Barents Sea in the winter. In January, the anticyclones are most frequent and High 1024 strongest over Siberia and Alaska/, with a weaker 1020 system over the central Arctic Basin and Greenland. 1020 High In July, the Aleutian Low disappears and the low-pressure area off Iceland shifts to southern Baffin Island in Canada 1016 (Canadian Low) (Figure 2·4). The pressure is low over Cen- tral Siberia and a weak ridge of high pressure over the Arctic 1032 1012 Ocean separates this low from the Canadian Low. High- 1008 1028 pressure areas are located around the North Pole and north 1000 of the Pacific Ocean (Barry and Hare 1974). Atmospheric Icelandic Low 1020 1024 circulation patterns are further discussed in chapter 3, sec- 1004 tion 3.2.

Elevation 2.3.3. Meteorological conditions 2 000 m 1016 1 000 m 1020 2.3.3.1. Air temperature Climate conditions in the Arctic are divided into maritime Figure 2·3. Mean atmospheric sea-level pressure (mb) in the Arctic in Jan- and continental subtypes. A maritime climate is characteris- uary (after Barry and Hare 1974). tic of Iceland, the Norwegian coast, and the adjoining parts of Russia. These areas have moderate, stormy winters. The are cloudy, but mild with mean temperatures of about 10°C. The average winter temperatures are –2°C to 1°C in the Icelandic lowland, –2°C at Bodø on the Norwegian coast, and –11°C at on the Russia coast (Barry 1024

1020 and Chorley 1992, EEA 1996). Figure 2·5 shows the distri- bution of January and July air temperatures in the Arctic. 1016

1012 A maritime climate is also found directly along the Alas- kan coast. This zone is very narrow because of the moun- Low tains of the Alaska and Coastal Ranges. Winters here are moderate and the summers are mild, but cloudy. The average

1004 temperature at Anchorage ranges from –5°C in winter to

1008 10°C in summer. Canadian Low Continental climate is found in the interior of the Arctic from northern Scandinavia toward Siberia, and from eastern

1008 Alaska toward the Canadian Arctic Archipelago, with much lower precipitation and significant differences between sum- mer and winter conditions (July means of 5-10°C; January 1012 means of –20° to –40°C) (Prik 1959). Over the ice-covered

1016 Arctic Ocean, both the ice and the underlying sea have a 1020 regulating effect on temperature. The minimum air tempera-

Elevation 1024 ture is moderated by heat conducted from seawater below 2 000 m High the ice. Generally, in the central Arctic, the average tempera- 1 000 m ture is between –30° and –35°C in winter and between 0° and 2°C in summer. Figure 2·4. Mean atmospheric sea-level pressure (mb) in the Arctic in July Moving depressions, and heat transported by ocean cur- (after Barry and Hare 1974). rents, have a warming effect on the climate which becomes 12 AMAP Assessment Report

January 2.3.3.2. Ocean temperature 90°E 180° As in the atmosphere, there is both annual and interannual variability in ocean temperature. This is most pronounced in the warmer water masses. Variability in cold Arctic waters is small, but important. In the North Atlantic, the ocean ap- pears to alternate between warm and cold states. The length of these states may vary, but fluctuations with periods of 3-5 years are most frequent. The varying temperature condition in the western North Atlantic is opposite to that in the east- ern North Atlantic. This means that when the Barents Sea is in a warm state, the coast of Newfoundland is in a cold state (Sundby pers. comm.). This feature is also found in the dis- tribution of ice. When there are heavy sea ice conditions in the northeast Atlantic, there is little ice in the Labrador Sea, and vice versa (Gloersen et al. 1992). There is also large var- iability in ice distribution in the Bering Sea, but at present, there is no evidence that this is linked to the variability in the Atlantic. The temperature state of the ocean appears to be closely 0° linked to atmospheric circulation, with a positive feedback 90°W mechanism existing between the atmospheric and oceanic circulations. It appears that high atmospheric pressure is as- -48 -43 -38 -33 -28 -23 -18 -13 -8 -3 2 7 9.5 °C sociated with low temperatures in the ocean while low pres- sure is related to a warmer ocean. Changes in ocean climate influence transport mechanisms and ice cover. In warm years, there is an increased transport of warm water masses to the Arctic, resulting in decreased ice cover. In cold years, July transport of warm water to the Arctic is reduced and sea-ice 90°E 180° coverage is greater (Ikeda 1990a, 1990b, Aadlandsvik and Loeng 1991).

2.3.3.3. Precipitation The total annual precipitation in the Arctic is generally less than 500 mm and typically between 200 and 400 mm (Losh- chicov 1965) (Figure 2·6). Along the Arctic coast, the pre- cipitation is higher, and over the central Polar Basin it is lower. Cold air contains less moisture, therefore, although

the frequency of precipitation may be high, the overall inten- 1000 600 400 600 600 800 400 600 200 600

300 800

800 600

600 600

400 300 0° 600 90°W 800 1000

300 150 600 300 200 -13 -8 -3 2 7 9.5 °C 600

800 Figure 2·5. Mean January and July surface air temperatures (°C) in the Arctic (Parkinson et al. 1987). apparent if one compares temperatures among stations at 600 1600 similar latitudes. The average January temperature of a sta- 400 tion in the Canadian Arctic Archipelago is approximately 20°C lower than the January temperature of a station at the 1200 400 600

1000 800 same latitude on Svalbard. The warming effect of the mov- 800 1600 1600 ing depressions extends as far as the northeastern parts of 1000 1200 the Barents Sea. During the summer season, temperature 1600 variations along the latitudes are much reduced, due to the moderating effect of the sun’s heat.

Figure 2·6. Distribution of precipitation (mm/y) in the Arctic (AARI 1985). Chapter 2 · Physical/Geographical Characteristics of the Arctic 13 sity is low. This explains why the total accumulation of nyas. Winds, or more precisely differences in air pressure snow is relatively low in winter over much of the Arctic. which cause winds, are often closely related to ocean circu- The spatial precipitation pattern in the Arctic can be ex- lation as discussed by Ikeda (1990b) and Aadlandsvik and plained in terms of the effects of elevation changes and Loeng (1991). proximity to maritime sources of moisture. Precipitation Surface winds are greatly affected by the presence of tem- levels decline with increasing distance inland from the oceans, perature inversions. In Greenland, katabatic winds are formed and in general, levels decrease in a west-east direction across as air in the dense, cold inversion layer flows down the slopes the in the direction of movement of most low- of the ice sheet toward the coast under the influence of gra- pressure systems. vity. These winds are especially well developed in winter The lowest precipitation levels on land are approximate- when the air comes into contact with the ice surface and is ly 140 mm/y, occurring in eastern Siberia, chilled. With the exception of these parts of Greenland, wind and Greenland. In general, total precipitation increases to speeds are generally slowed by temperature inversions as the above 600 mm/y from these areas toward the Atlantic and air is effectively isolated from faster-moving air currents Pacific Oceans (Sugden 1982). above (Sugden 1982). Maritime areas in the subarctic have much higher preci- Two dominant air currents in the Arctic are associated pitation. In southern Iceland, the annual precipitation ranges with cold air flowing in winter from the high-pressure zone from below 800 mm to over 3000 mm, and on mountains over northern Siberia to the Pacific, and air flowing northwest and glaciers it can exceed 4000 mm (Einarsson 1984). The from the high-pressure area over the Canadian Arctic toward precipitation decreases toward the east and north, with 700- the low pressure over the Atlantic. These winds result in very 2000 mm/y at Bodø to less than 400 mm/y at Murmansk, severe climatic conditions in the Arctic, and in Canada, these Russia and , Svalbard (EEA 1996). conditions persist into the early summer (Sugden 1982).

2.3.3.4. Cloud cover 2.4. Physical/geographical description An important climatic feature of the Arctic is the presence of the terrestrial Arctic of persistent and extensive stratus cloud cover over the po- 2.4.1. General geographical description lar oceans. The cloud cover occurs in well-defined layers separated by clear interstices. The structure of the clouds is The vast Arctic terrestrial landscape, covering an area of ap- related to the large-scale transport of relatively mild, humid proximately 13.4 106 km2 within the AMAP boundary, is air into the Arctic Basin, the boundary layer turbulence, and very diverse (Figure 2·7), with large tracks of land covered the optical properties of the liquid water droplets. Clouds by glacial ice. Glaciers are large masses of ice that flow un- are formed largely during the summer season; the cloud der their own weight. They form where the mean winter cover varies from a summer amount of 70-90% to 40-60% snowfall exceeds the mean summer melting. Melting, re- in winter (Landsberg 1970). freezing and pressure gradually transform the snow into ice. During periods of cold air outbreaks from the Arctic Ba- Greenland, often described as the largest island in the sin, clouds are formed by cooling of the boundary layer air world, is actually comprised of numerous mountainous is- previously at higher temperatures because of the relatively lands almost entirely covered with a permanent ice cap up to warm sea surface underneath. Characteristic cloud strips fol- 3000 m thick (Stonehouse 1989, Bjerregaard 1995). It spans lowing the wind direction cover large areas of the open sea. 24 degrees of latitude (2670 km), is 1200 km across at its widest point, and covers an area of some 2 186 000 km2. The main tracts of ice-free land are in the southwest, the 2.3.3.5. Fog north (Peary Land) and the northeast (north of Scoresby- A characteristic feature of Arctic weather is fog. Parts of the sund). Along the Greenland coast, outlet glaciers flow from Arctic are extremely foggy due to the juxtaposition of cold the ice sheet to the sea. Glaciers terminating in the sea per- air overlying warmer ocean waters in some areas and warm iodically break off, or calve, forming icebergs. air overlying cold ice in others. In some areas, it is typical to Iceland is located south of the Arctic Circle (66°32'N). have more than 100 days per year with fog (SCOR 1979). This mountainous and volcanically active island lies on the In summer, the ice retreats northward, exposing open water, mid-Atlantic ridge. Its average height is approximately 500 and warm air moves in over the ice and cold water. Sublima- meters above sea level. One quarter of the country is less ting ice and condensing water form thick fog fields that en- than 200 m above sea level. It has an area of 103 000 km2, velop the marginal ice zones, with peaks in relative humidity with 11% of its surface covered by glaciers and more than over water in August. In winter ‘sea smoke’ or steam fog 50% of its land surface unvegetated (Stonehouse 1989, Min- forms over open water leads in the pack ice (SCOR 1979). istry for the Environment 1992). The Faeroe Islands, with a total area of 1399 km2, are lo- cated 430 km southeast of Iceland. The terrain is mountain- 2.3.3.6. Wind ous with an average elevation of 300 m. Winds are particularly important for the Arctic surface en- Svalbard and are Arctic archipelagos vironment, as they can greatly augment the chilling effect of of 63 000 and 10 000 km2, respectively. These mountainous low temperatures. The generally open landscape of the Arc- islands, and others lying to the north of Eurasia, are about tic region means that winds are not greatly slowed by fric- 90% covered by ice. tion at the ground level (Sugden 1982). Wind is an impor- The Fennoscandian Arctic area covers roughly 300 000 tant factor in snow distribution, causing scouring in exposed km2, but most of this area is subarctic due to the warming areas and deposition in sheltered locations (Killingtveit and influence of the Gulf Stream extension (Stonehouse 1989, Sand 1991). Encyclopedia Britannica 1990). In the marine environment, wind affects sea surface sta- The Kola Peninsula (ca. 145 000 km2) on the Russian bility and increases mixing in the water column. It also in- mainland is also subarctic and contains many lakes. Perma- fluences ice drift (Vinje 1976) and the formation of poly- frost is absent, except for sporadic occurrences at the tip of 14 AMAP Assessment Report

s nd la tian Is u Kamchatka le A

Amur

Y Bering u

k Sea Mts. Sea o

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e R

g

i n v a e R r Mts. a sk Bering la ALASKA e A Strait g (USA) River Alda a id n Kolym nge R Ra Chukchi i

ins s

M o u n t a k ky Sea e

c k y o s

R o o r g L

Mackenzie r e d e i n Mountains B East h a

C R R Siberian iv k e Sea s r Ma iver n ckenzie R Beaufort ya Great Slave ho Lake Sea erk New V River Lake Siberian Islands Athabasca Lake Canada Banks Laptev Baikal CANADA Basin Arctic Sea Island Ocean Victoria Central Island T aym Makarov ir P Siberian Lake en in Basin s Upland Winnipeg u Severnaya la Amundsen Zemlya Alpha Ridge isey Basin Yen

ey River Hudson Ellesmere Yenis Bay Island Ri Lomonosov Ridge Nansen RUSSIA er ve Foxe iv r Franz Kara R Basin Basin b James Josef Sea O Bay Nansen Gakkel Ridge Land West Siberian iver h R Novaya tys Zemlya Ir Baffin Fram Ob R ive Bay GREENLAND Strait Svalbard r Irty sh Labrador () Spitsbergen R Mountainsiv Davis e Barents r Strait Lake Bear Island Sea Saint Jean Ka Kola m Peninsula a Jan Mayen R i White v Sea N e orth Dvina r er Lake Riv lga Onega o ICELAND Norwegian V Sea Lake Ladoga V Gulf of o Faeroe Islands Bothnia lg Atlantic a Ocean

SWEDEN North DANEMARK Sea

R h e in

- 5 000 - 3 000 - 2 000 - 1 000 - 500 - 100 0 50 100 200 300 500 1 000 1 500 2 000 3 000 4 000 m

Figure 2·7. Topography and bathymetry of the Arctic (based on the ETOPO5 data set, NOAA 1988). the peninsula, and the coasts are ice-free (Ives 1974, Luzin et ered by glaciers and a small ice cap. The southern island is al. 1994). The Russian Arctic west of the smaller (33 000 km2), largely ice-free, and characterized by shows much variation in landscape, but large areas consist of large coastal , especially in the southern parts. flat, poorly drained lowlands with marshes and bogs. The Si- Alaska’s Arctic, according to the AMAP definition, ex- berian coast is generally flat and includes the deltas of many tends over an area of 1.4 106 km2, and is dominated by large, north-flowing rivers. Ice-covered mountains are char- rugged mountain ranges that stretch across the state in the acteristic of the Russian peninsulas of Taimyr and Chukotka. south and north, reaching a maximum height of 6194 m at In eastern Siberia, there are several mountain ranges (e.g., Mount McKinley. Extensive glaciers are found in the south Verkhoyansk, Chersky and Momsky) with peaks reaching central and southeastern mountains. These ranges give way heights of over 2500 m. The entire area of Arctic Russia to foothills and low-lying coastal tundra plains in the south- within the AMAP boundary is approximately 5.5 106 km2. west and along the northern coast of Alaska. Extending The numerous islands of the Russian Arctic cover an area westward into the Pacific Ocean beyond the Alaska Penin- of 135 500 km2. The largest of these is , an sula are the volcanic Aleutian Islands (Stonehouse 1989). archipelago with two main islands. The northern island is The Canadian Arctic landscape covers an area of approx- mountainous, with about half of the 48 000 km2 area cov- imately 4 106 km2, comprised of the northern Canadian Chapter 2 · Physical/Geographical Characteristics of the Arctic 15 mainland in the south and the Arctic archipelago to the north. At the most western boundary of the mainland is the Yukon Plateau, consisting of rolling uplands with valleys and isolated mountains. Southwest of this plateau are the East Siberian Coast Mountains with extensive glaciers. To the northeast Highlands North American are the Mackenzie Mountains. These mountain ranges give Cordillera way to the Interior Lowlands, comprised of plateaus rang- Interior ing in height from 1200 m in the west to 150 m in the east. Plain This region, which is transected by the , is Hudson Central characterized by extensive wetlands. The large Great Bear Lowlands Siberian Arctic Plateau and Great Slave Lakes extend from the Interior Lowlands Islands eastward into the . The Shield extends to West Siberian the east coast and contains numerous lakes and the vast ex- Lowland panse of Hudson Bay (National Wetlands Working Group Canadian Shield Ural 1988, Prowse 1990). Mountains East European The Canadian Arctic Archipelago extends far to the north Plain Baltic of the mainland. Flat to rolling terrain is characteristic of Shield North the High Arctic islands in the western and central archipe- Atlantic lago (e.g., Banks, Melville, Victoria, Bathurst and Prince of Islands Wales Islands). The northeastern islands (Baffin, Devon, Ellesmere and Axel Heiberg) contain rugged, ice-capped mountains up to 2000 m in height (Prowse 1990, Woo and Gregor 1992, Sly 1995). AMAP boundary AMAP Figure 2·8. Geologic and physiographic regions of the Arctic (after Linell 2.4.2. Geology and physiography and Tedrow 1981, by permission of Oxford University Press). The major physiographic regions and bedrock geology of the Arctic are presented in Figures 2·8 and 2·9, respectively. Greenland, and a vast region of the Canadian Arctic, from the Atlantic Ocean in the east to Great Bear Lake and in the west, is underlain by the Canadian Shield. This Precambrian, crystalline rock mass is exposed in some areas and covered by glacial deposits and thin soil in others. The Canadian Shield extends northward to in- clude Baffin Island. The remaining islands in the Canadian Arctic Archipelago are primarily made up of and Mesozoic sedimentary rocks. Along the southwest coast of Hudson Bay are the Hudson Lowlands, comprised mainly of Lower Paleozoic rock and covered by Quaternary sedi- ments. To the west of the Shield are the Interior Plains made up of Devonian and sedimentary formations. The North , a wide belt of high moun- tains and plateaus of Paleozoic, sedimentary origin, extend along and Alaska. In Alaska, these moun- tains merge to the north with the Arctic Foothills, which descend still farther north into a coastal plain (Linell and Tedrow 1981, Prowse 1990, Natural Resources Canada 1994). Iceland has been created by volcanic activity along the mid-Atlantic ridge during the last 20 million years. New volcanic rock is constantly being added and about one- Mainly sedimentary rocks Intrusive and metamorphic terrains tenth of Iceland is covered by lava deposited since the last Mixed volcanic, Tectonic assemblages, ice age (Einarsson 1980). The Aleutian Islands to the west pyroclastic and sedimentary schist belts, melanges of Alaska are also volcanic. Mainly volcanic rocks Ice Northern Fennoscandia and the Kola Peninsula are com- Plutons prised of ancient, crystalline rocks forming the . Unclassified East of this region, from the to the Ural Moun- Figure 2·9. Bedrock geology of the Arctic (Geological Survey of Canada tains, lies the East , made up of sedimentary 1995). rock covered by a deep layer of glacial drift. The Ural Moun- tain complex, which includes Novaya Zemlya, is a region Anabar Shield and peripheral sedimentary rocks. To the of folded Paleozoic bedrock, covered thinly with glacial de- north, the Taimyr Peninsula contains a folded mountain posits. The other Russian Arctic islands are also primarily complex of sedimentary rocks, overlain by shallow soils. formed by sedimentary formations of the Paleozoic Era. The region east of the Lena River is similarly comprised of The West Siberian Lowland, comprised of till-covered sedi- folded sedimentary mountains, with some volcanic rocks. mentary rocks, extends from the Urals to the Yenisey River. Glacial drift is discontinuous in this region (Linell and Te- From here, eastward to the Lena River, is the Central Sibe- drow 1981). Low plateaus and plains are characteristic of rian Plateau. This till-covered region is underlain by the the region through which the Lena River passes and of the 16 AMAP Assessment Report

Sand Clay and silt Gravel Well drained Permafrost Active layer site Impervious layer at surface forces water to percolate through Depth of summer thaw (bottom of active layer) unfrozen sections (taliks) within permafrost Water percolating only Water percolating A during the warm season throughout the year B Poorly drained A - Groundwater above the permafrost (suprapermafrost water) site B - Groundwater within the permafrost (intrapermafrost water) C - Groundwater below the permafrost (subpermafrost water) C B Small lake Permafrost with much ice C

River

C C

Figure 2·10. Occurrence of groundwater in permafrost areas (after Mackay and Løken 1974, Linell and Tedrow 1981).

reach depths of 600-1000 m in the coldest areas of the Arc- tic (Stonehouse 1989). The distribution of permafrost is broadly determined by climate, particularly air temperature and the resultant en- ergy balance between the air and the ground. Several sec- ondary factors which affect permafrost occurrence include elevation, composition and color of the ground surface, ground aspect, soil moisture, and extent and type of plant cover. Permafrost is generally not found under large bodies of water greater than three meters deep, the maximum depth to which winter ice develops. The insulating effects of gla- ciers and extensive snow cover also reduce permafrost devel- opment (Ives 1974). Figure 2·11 shows distribution of con- tinuous and discontinuous permafrost north of 50°N. Per- ennially frozen ground occurs throughout the Arctic and ex- tends into the forested regions to the south. Along the north- ern coastlines, frozen grounds meet the sea, with permafrost extending under some shelf seas. Permafrost influences soil development in the north. In general, Arctic soils are either poorly drained and under- lain by solid, ice-rich permafrost, or well drained and situ- ated over dry permafrost. Poorly drained soils are found in Continuous permafrost 85-90% of the Low Arctic and in the few wet meadows of Discontinuous permafrost the High Arctic. Well-drained soils are common in the ex- Ice cap/glacier tensive, sparsely vegetated areas of the High Arctic, and are scattered throughout the Low Arctic in areas where Figure 2·11. Circumpolar permafrost distribution (CAFF 1996). water can escape, such as on steep slopes and beach ridges. Oxidation processes in these drier soils result in lower or- northern margin of Siberia from the Taimyr Peninsula to ganic matter content compared to wetter soils (Rieger 1974, the Kolyma River (Sachs and Strelkov 1961 in Linell and Everett et al. 1981). Tedrow 1981). During the summer, the upper layer of soil in the Arctic thaws and is termed the active layer. Its depth varies accord- ing to temperature, ground material, soil moisture content 2.4.3. Permafrost and soils and plant cover, ranging from as little as several centimeters Permafrost, or perennially frozen ground, is defined as ma- in far northern wet meadows to as deep as a few meters in terial that stays at or below 0°C for at least two consecutive warmer, more southern, dry areas with coarse-grained soils summers (Woo and Gregor 1992). It may consist of soil, (Ives 1974) (Figure 2·10). Soil-forming processes are largely bedrock or organic matter. Spaces within the ground mater- restricted to the active layer, which is unstable due to frost ial may be filled with ice in the form of ice lenses, veins, lay- action during repeated freezing and thawing. Frost action ers and wedges. When very little or no ice is contained in results in characteristic surface features, such as frost scars, the frozen substrate, this is referred to as dry permafrost stone circles, mud circles, solifluction lobes and stone stripes (Figure 2·10) (Linell and Tedrow 1981). Permafrost may (Rieger 1974, Stonehouse 1989). Chapter 2 · Physical/Geographical Characteristics of the Arctic 17

2.5. Arctic freshwater environments growing before the end of winter. Icings formed by dis- charge from intra- or subpermafrost groundwater continue 2.5.1. Rainfall and snow to build until temperatures climb above 0°C in spring. In The Arctic is characterized by short summers and therefore cases of large icings, spring melt and runoff can result in sig- short periods with rainfall. The remaining precipitation falls nificant redistribution of groundwater (van Everdingen 1990). as snow, which accumulates as snowpack over the winter. Groundwater is quite extensive in the Arctic. For exam- Snowpack duration, away from the moderating influences ple, approximately two-thirds of the Yukon in the Canadian of coastal climates, ranges from about 180 days to more Arctic is underlain by aquifers (Hardisty et al. 1991). The than 260 days (Grigoriev and Sokolov 1994). largest groundwater aquifers in Iceland have been mapped High levels of solar radiation reaching northern latitudes in Elíasson (1994). These are generally found in highly per- in spring result in rapid snowmelt. Spring runoff comprises meable lava. Groundwater represents an important source 80-90% of the yearly total, and lasts only two to three weeks of water in some Arctic countries. (Linell and Tedrow 1981, Rydén 1981, Marsh 1990). Infil- tration of this flush of water into the ground is constrained 2.5.3. Wetlands by the permafrost. Thus, spring meltwater may flow over land and enter rivers, or accumulate into the many mus- Wetlands and saturated soils are characteristic features of kegs, ponds and lakes characteristic of low lying tundra the Arctic since moisture received from rain and snowmelt areas (van Everdingen 1990). Summer sources of water in- is retained in the active layer above the permafrost barrier. clude late or perennial snow patches, glaciers, rain, melting Due to the higher levels of precipitation received at lower of permafrost, and groundwater discharge (Rydén 1981, latitudes, wetlands are more common in the Low Arctic van Everdingen 1990). than the High Arctic. In general, wetlands are sparsely dis- tributed throughout the Arctic, but tend to have significant local concentrations. 2.5.2. Groundwater Arctic wetlands are distinct due to the unique climatic Groundwater levels and distribution within the Arctic are conditions under which they were formed. Permafrost un- greatly influenced by permafrost. Permafrost affects the derlies almost all Arctic wetlands. A number of different amount of physical space in which groundwater can be held forms of wetlands exist in the Arctic and are described be- and the movement of water within drainage systems. There low (National Wetlands Working Group 1988). are three general types of groundwater: suprapermafrost, intrapermafrost and subpermafrost (Figure 2·10). Supra- 2.5.3.1. Lowland polygon bogs and fens permafrost water lies above the relatively impermeable per- mafrost table in the active layer during summer, and year- Two types of lowland polygons are found in the Arctic, those round under lakes and rivers that do not freeze. Intraper- with a low center and those with a high center (Figure 2·12). mafrost water resides in unfrozen sections within the per- When soil temperatures fall below –15°C in winter, the ice mafrost, such as tunnels called ‘taliks’, located under allu- within the soil contracts forming cracks and eventually ice vial flood plains and under drained or shallow lakes and wedges. Low-center polygons are bowl-shaped with the swamps. Subpermafrost water is located beneath the per- mafrost table and its depth below the surface depends on the thickness of the permafrost. In this latter case, the perma- frost acts as a relatively impermeable upper barrier. These three types of aquifers, which may be located in bedrock or in unconsolidated deposits, may interconnect with each other or with surface water (Mackay and Løken 1974, van Everdingen 1990). Generally low levels of annual precipitation in the Arctic restrict the recharge of groundwater. In addition, infiltra- tion of water to aquifers is restricted by permafrost year- round and by the frozen active layer for up to ten months of the year. Frozen substrate does not entirely prevent water from seeping through to aquifers, but slows the rate of infil-

tration by one or more orders of magnitude compared to KATHERINE MCLEOD unfrozen ground (van Everdingen 1990). The degree of groundwater recharge is influenced by the material comprising the substrate. Recharge is greatest in regions with coarse-grained, unconsolidated material and areas with exposed bedrock containing channels or frac- tures which allow passage of water. Infiltration, and there- fore recharge, is least in areas covered by fine-grained de- posits such as silt and clay (van Everdingen 1990). Groundwater is discharged via springs, base flow in streams, and icings. These discharges can be fed by supra-, intra- or subpermafrost water. Perennial springs are gener- ally fed by subpermafrost aquifers and less commonly by intrapermafrost water. Icings (also known as aufeis or na- leds) are comprised of groundwater that freezes when it

reaches the streambed during winter when base flow freezes. KATHERINE MCLEOD When fed by suprapermafrost water, icings generally stop Figure 2·12. Low and high-center polygons. 18 AMAP Assessment Report a Sphagnum peat Sedge-moss peat Permafrost table Mineral soil Ice 2.5.3.3. Snowpatch fens In the High Arctic, snow patches form below the brows of hills on the lee side. With accumulations of up to 2 m, melt- ing of this snow can provide water to the slopes below throughout the summer. If the slope of the hill is gradual, this meltwater will flow in sheets, creating wetlands along its course. Low-center polygons 5 m

Amorphous peat Organic-mineral mixture 2.5.3.4. Tundra pool shallow waters Sphagnum peat Sedge-moss peat Mineral soil b Permafrost table Ice Dotted throughout the landscape of the northern Low Arctic and the High Arctic are small ponds, usually less than 1 ha in area and less than 0.5 m deep. The edges of these pools tend to be peaty.

2.5.3.5. Floodplain marshes High-center polygons Floodplain marshes are located in active floodplains along- Figure 2·13. Low-center and high-center polygon development (after Nat- side river channels. These marshes tend to have high water ional Wetlands Working Group 1988). levels during spring melt and low levels in the fall. Water levels in floodplain marshes located in estuaries and deltas edges pushed up by surrounding ice wedges (Figure 2·13a). near the sea are additionally affected by the tide. Due to The depressed centers of these polygons fill with water, cre- high sedimentation loads in these marshes, the build-up of ating small ponds. The peat layer in low-center polygons is organic matter is limited. thin. Over time, the peat builds up, gradually filling the de- pression and forming a raised or high-center polygon. High- 2.5.3.6. Floodplain swamps center polygons, therefore, represent a more advanced stage of lowland polygon development (Figure 2·13b). These po- Similar to floodplain marshes, floodplain swamps are found lygons vary in size, but are commonly about 8 m in diame- in river deltas, but have open drainage due to an unrestricted ter (National Wetlands Working Group 1988). connection to the river channel. Water levels in these swamps Bogs and fens are both referred to as mires, i.e., areas are highest in spring and gradually decline until the fall. with appreciable peat accumulation. When the peat is fairly Again, due to heavy sedimentation, little organic matter ac- acid (pH 3.0-5.0) the wetland is called a bog. The peat in cumulates in the soils of these swamps. fens is more neutral due to regular flooding with base-en- riched waters (Moore 1981). 2.5.3.7. Wetland occurrence In the Canadian Arctic, approximately 3-5% of the land 2.5.3.2. Peat mound bogs area is covered by wetlands. Areas of high occurrence (be- Peat mound bogs are simply peat-covered mounds, 1-5 m in tween 20 and 75% coverage) include the Yukon coastal diameter, that rise about 1 m above ground (Figure 2·14). plain, the Mackenzie Delta, and parts of the Arctic islands As peat builds up in an area of a wetland, the insulating ef- (National Wetlands Working Group 1988). fect causes thinning of the active layer beneath, and growth Mires are uncommon in Greenland, and in Alaska they are of segregated ice under and within the peat, thereby form- restricted to the northern mountains. In Norway, only 0.9% ing a dome. of the Arctic region is classified as wetland and bog area. reports 21% of its Arctic land area as mire (CAFF 1994). In Finland, approximately half of the original wet- FenPeat mound bog Fen land area has been disturbed for forestry, leaving about 15% of the country covered by wetlands (Keltikangas et al. 1986). In the Russian Arctic, large areas are dominated by bogs and marshes including the Kola Peninsula, West Siberia, the 0 0 Yamal Peninsula and the lowlands of the Yana, Indigirka, and Kolyma River basins (Plancenter Ltd. 1991, Bliss and Matveyeva 1992). 1 m 1 m 2.5.4. Rivers Two main types of rivers occur in the Arctic, those that have 2 m 2 m 012 3 4 5 6 7 8 9 10 11 m headwaters within the Arctic and those with headwaters far- ther south (Woo 1992). Most of the large Arctic rivers begin Fibric sphagnum peat Humic peat their flow south of the Arctic, including the major rivers of Siberia (Ob, Yenisey, and Lena) and the Mackenzie River in Fibric brown moss peat Mineral soil Canada (Mackay and Løken 1974). The mean annual runoff Mesic brown moss peat Permafrost table to the Arctic Ocean from the largest Arctic rivers is shown in Figure 2·15. Figure 2·14. Cross-section of a peat mound bog (after National Wetlands Flow in Arctic rivers is largely influenced by rain, snow- Working Group 1988). melt and ice melt because of the drainage barrier of the per- Chapter 2 · Physical/Geographical Characteristics of the Arctic 19

Freeze-up in Arctic rivers begins with the drop in tempe- ratures in the fall. The progression of freeze-up in rivers is similar to that of lakes (refer to section 2.5.5). In addition to the wind and wave action which causes vertical mixing of lake and river water, turbulent flow in rivers can have the

Yukon River same effect, thereby creating a thicker surface cooling layer 210 km3/y Kolyma in the autumn. Mean dates for river freeze-up in the Arctic 132 km3/y are shown in Figure 2·17 (Mackay and Løken 1974). Mackenzie 3 Lena 333 km /y 525 km3/y Yenisey 603 km3/y 1.V 20.IV Nelson River 10.V 75 km3/y 1.IV Ob 10.IV 20.V 404 km3/y 1.V Pechora 10.V 140 km3/y 1.VI 10.III 20.V Northern Dvina 3 10.VI 106 km /y 20.III 1.V 10.V 1.V 20.IV 20.V 1.VI 1.IV 10.VI 10.IV

20.IV 1.V 10.VI

Discharge 20.VI

20.IV Watershed 10.VI 1.VI Catchment areas 20.V 1.VI 20.V 10.V 1.V 10.V Figure 2·15. Arctic Ocean watershed and catchment areas of some rivers 1.V and annual runoff (km3/y) of major rivers to the Arctic Ocean. 20.IV mafrost and the limited water storage capacity of the thin active layer (Newbury 1974 in Woo 1992). River flow is also affected by lake/reservoir storage and by groundwater input (e.g., the Lena River in winter) (Gordeev and Sidorov 1993). Most Arctic rivers exhibit an Arctic nival regime, meaning that their main flow takes place during the period Figure 2·16. Mean dates of river break-up in the Arctic; month number in Roman numerals (after Mackay and Løken 1974). of spring melt. When the melt is completed, water levels in the river drop to base flow only. Some northern rivers dis- play a proglacial regime, flowing throughout the summer due to input from glacial melt. Rivers flowing through wet- lands follow a wetland or muskeg regime, with the main 21.XI 1.XII 20.XI 1.XI flow occurring with the spring snowmelt when the ground 10.XI 20.X 10.XI 1.XI 10.XI 1.XI is still frozen (Woo 1992). 10.XII 10.X 10.I 20.XI 20.X 10.XI 10.X In some areas, such as the Canadian Cordillera, rivers 1.I 20.X 20.XII tend to be erosive, undercutting their banks and creating 10.XII 1.XII 1.XII 20.XI large, braided channels. Therefore, these rivers have large 10.XI 20.XI sediment loads and leave behind deposits of this sediment 10.XI 1.XI along their course as braided channels and eventually as 20.X 1.X large deltas (Stonehouse 1989), and contribute to bottom 10.X 10.XI 20.X sediments in lakes and reservoirs. Other parts of the Arctic, 20.XI 1.XI such as the Precambrian shield, lack the surficial deposits 10.XI 20.XI necessary to provide a source of river sediment. The break-up of ice in Arctic rivers begins at the river

20.XI 10.XI edge as melt water flows in from adjacent river banks and 10.XI 1.XII slopes. Increased flow onto the surface breaks the ice cover 10.XI into pieces. Leads develop across the river at locations of in- 20.XI coming streams. Intermittent and slow flow of the river be- gins as the ice edge gradually loosens from the riverbank. Ice jams form at narrow and shallow areas of the river, eventu- ally giving way under the pressure of water coming in from tributaries and with continued melting and ice abrasion. Figure 2·17. Mean dates of river freeze-up in the Arctic (after Mackay and When the ice jams break up there is an initial surge of water Løken 1974). followed by a drop in water level, which leaves pieces of ice stranded along the river bank. Mean break-up dates of Arctic 2.5.5. Lakes rivers are shown in Figure 2·16 (Mackay and Løken 1974). Arctic rivers tend to remain cool throughout the short The eastern and central North American and western Eur- summer season due to the addition of cold melt waters. asian Arctic regions were covered with glaciers during the Small, shallow streams may be quickly warmed by solar epoch. Glaciation of eastern Asia was less exten- radiation to 10-20°C, but these warm waters have little ef- sive. These large glaciers carved out the land as they moved fect on the low temperatures of larger rivers systems. over it, gouging out topsoil and broken rock. The many de- 20 AMAP Assessment Report pressions left behind filled with water when the glaciers With the onset of cooler weather and fall storms in mid- melted, forming lakes. August, Arctic lakes lose heat rapidly and mix completely Following the retreat of the continental glaciers, the land throughout their depth. Because the lakes are unprotected which had been pushed downward by the weight of the ice, by trees and high winds are common, Arctic lakes tend to began to rise, a process called isostatic rebound. This re- cool well below the temperature of maximum density (4°C), bound is still occurring today, and though it is at a much with the entire water column often reaching 0°C before slower rate than when it began, eastern Hudson Bay, for ex- there is significant ice formation at the surface. Freeze-up oc- ample, continues to rise at a rate of one meter per century. curs between the first week in September and mid-October, New lakes are thus still being formed as gouged land rises depending upon the latitude and size of the lake. Ice thick- up out of the sea. Lakes closer to sea level are often younger ness increases linearly until April or May, reaching depths than those at higher elevations (Welch and Legault 1986). between 1.5 and 2.5 m (first year ice). Ponds with depths Other types of natural lakes exist in the Arctic. Kettle less than maximum ice thickness (typically 2.0-2.2 m) freeze lakes result from the thaw of buried glacier ice (Washburn to the bottom. Thus, Arctic lakes are partly frozen for 9-12 1979). Thermokarst lakes are formed in depressions that months of the year (Welch et al. 1987, Welch 1991). result from permafrost melting. Ice-dammed lakes are more common in the Arctic than elsewhere and in Greenland all 2.5.6. Estuaries the larger lakes are of this type. These lakes are prone to periodic draining (Mackay and Løken 1974). Estuaries are semi-enclosed, coastal bodies of water, con- There are innumerable small lakes in the Arctic. In the nected to the open ocean, and containing seawater diluted Province of Murmansk in Russia, there are over 100 000 by freshwater from land drainage (Lauff 1967, Pritchard lakes, the largest of which is Lake Imandra with an area of 1967). In a broad sense, river deltas, fjords and bays may be 812 km2 and a maximum depth of 67 m (NEFCO 1995). considered as estuaries, and they are important parts of the Iceland, Sweden and Finland have approximately 2.7, 5.2 coastal zone. With the exception of Norwegian and Icelan- and 5.8%, respectively, of their land area occupied by lakes. dic fjords, they are influenced by ice cover for most of the Only about 0.5% of Alaska is covered by freshwater (CAFF year. Fast ice often starts to develop in October, and remains 1994). The Canadian Arctic contains many lakes, including in place until break-up in June (Macdonald et al. 1995, Pfir- the large Great Bear (31 326 km2) and Great Slave (28 568 man et al. 1995). Thus, for most of the year in the Arctic, km2) Lakes located on the mainland (Mackay and Løken river runoff enters the ocean under an ice cover. 1974). In the central Canadian Arctic, 20% of the land sur- The coastal zone is the interface between the terrestrial/ face is covered by water. freshwater processes and the oceanic processes. Deltas and There are also artificial lakes or reservoirs within the estuaries play an important role in sedimentation in fresh- Arctic that have been created along Arctic rivers for the water systems and strongly influence contaminant transport purpose of hydroelectric power generation. In Canada and to oceans. There is a significant difference between summer Russia, some of these reservoirs are quite large, for exam- and winter regimes of estuarine zones. The summer regime ple, those for the project in Canada, and the is characterized by maximum river discharge, intensive Kransnoyarskoye Reservoir on the Yenisey River in Siberia. chemical and biological processes, and high sedimentation The time at which Arctic lakes become ice-free is largely rates. During winter, the freshwater runoff and fluxes of sus- dependent on June temperature and windspeed (Welch et al. pended and dissolved substances are low. l987). Ice thaw begins when meltwater from the surrounding watershed flows out onto the lake ice and enters cracks and holes in its surface. Shore leads then develop along the lake’s 2.6. Arctic marine environment perimeter, eventually breaking the connection of ice with the 2.6.1. Geographical area and bathymetry edges and bottom of the lake. The water on the ice surface gradually melts through the free-floating ice. A combination The circumpolar Arctic region is dominated by the Arctic of melting temperatures and weather activity continue the Basin. The Arctic marine area within the AMAP boundary thawing process (Mackay and Løken 1974). Ice-out in Arctic includes the Arctic Ocean, the adjacent shelf seas (Beaufort, lakes ranges from early July in the south to mid-August in the Chukchi, East Siberian, Laptev, Kara, and Barents Seas), the High Arctic, with some lakes at very high latitudes remaining Nordic Seas (Greenland, Norwegian, and Iceland Seas), the partly or entirely ice-covered throughout the year (Rust and Labrador Sea, Baffin Bay, Hudson Bay, the Canadian Arctic Coakley 1970, Schindler et al. 1974, Welch et al. 1987). Archipelago and the Bering Sea. This represents an area of The period of peak incoming solar radiation has already approximately 20 106 km2. The connection with the shal- passed by the time the ice is off Arctic lakes, and much of low Bering Sea (and the Pacific Ocean) occurs through the the radiation received prior to this time is used to melt the narrow Bering Strait, while the main connection with the At- ice (Schindler et al. 1974, Welch et al. 1987). Therefore, lantic Ocean is via the deep and the Nordic Seas. water in Arctic lakes has little opportunity for warming. The Arctic Ocean is divided into two deep basins, the Freshwater is densest at 4°C and sinks below water that is Eurasian and the Canadian, by the transpolar Lomonosov warmer or colder than this temperature, thereby producing Ridge (Figure 2·7). The Canadian Basin is transected into stratification. Weak thermal stratification is found in Low the Makarov and Canada Basins by a ridge in the north, the Arctic lakes where surface water has greater opportunity to Alpha Cordillera, and reaches depths of more than 3500 m. warm up, compared to the High Arctic, where lakes tend to The continental shelf is narrow off most of Arctic North be vertically mixed (Mackay and Løken 1974, Welch et al. America, extending only 50-100 km from the coast, except 1987). Small, shallow lakes throughout the Arctic, which in the southeastern , where it reaches some 150 lose their ice quickly, may become quite warm (>10°C). km offshore (French and Slaymaker 1993). Such lakes do not stratify due to surface wind mixing. Max- The Eurasian Basin is smaller but deeper than the Cana- imum surface water temperatures range from about 15°C dian Basin, reaching depths of 4000 m. It is bisected by the in small lakes near the treeline, to 4-6°C in ice-free lakes narrow Nansen Cordillera into the Amundsen and Nansen north of 75°N (Welch, unpubl.). Basins. North of Siberia, the continental shelf is vast and Chapter 2 · Physical/Geographical Characteristics of the Arctic 21

1.0 8.0 5.0 0.0 -1.0

12.0

5.0 -1.7 -1.5

3.0

10.0

-1.0

0.0 2.0 -1.5 1.0

0.0 -1.8 -1.0

2.0 1.0 -1.8 -1.65 3.0 -1.8 4.0 -1.7 5.0 -1.5

-1.7 -1.7 5.0 -1.6 -1.8 -1.5 -1.4 -1.3 -1.7 -1.2 -1.1 -1.8 -1.5 -1.7 -1.0 -1.8 1.0 0.0 -1.7

0.0 -1.6 -1.4 -1.0 -1.3 -1.5 -1.7

Winter

16.0 15.0 5.0 19.0

2.0 15.0 10.0 12.0

0.0

15.0

5.0

0.0

11.0

10.0

6.0

0.0 5.0 4.0 -0.5 1.0

5.0

15.0 10.0

17.0

-1.7 -1.0 3.0 10.0 -1.5 -0.5 0.0 -1.0 1.0 2.0 -0.5 0.0 1.0 10.0 3.0 12.0 5.0 2.0 5.0 8.0 10.0 8.0 3.0 4.0 10.0 10.0 4.0 12.0 5.0

13.0

Summer 10.0 9.0 13.0

Figure 2·18. Winter and summer surface water temperatures (°C) in the Arctic Ocean and adjacent seas (USSR Ministry of Defense 1980). extends up to 900 km from the coast (Sugden 1982, Mac- rature between winter and summer. Due to ice coverage, donald and Bewers 1996). the temperature in this area is close to the freezing point year-round. In the shelf areas, surface water temperatures in winter are close to freezing (just below –1°C), while dur- 2.6.2. Hydrographic conditions in the Arctic ing summer they may increase to 4-5°C due to heating from Ocean temperatures within the AMAP area show large var- the sun. In areas influenced by Atlantic and Pacific water, iation depending on latitude and the influence of warm At- there may be greater seasonal variability, for example in the lantic and Pacific water. Figure 2·18 shows surface ocean northeast Atlantic and parts of the Bering Sea. In these areas temperatures in the Arctic during winter and summer. In the temperature remains higher than 0°C throughout the the Arctic Ocean, there are only small variations in tempe- year (USSR Ministry of Defense 1980). 22 AMAP Assessment Report

33.5 34.0 34.5 32.0 33.0 35.0

34.0

35.5

31.5 32.5 35.0 31.0 30.0

33.0 34.0

32.5

34.5 30.5 32.0 35.0 31.0 31.5 35.0 32.0 35.0 33.0 31.0 33.0 34.0 30.0 29.0 34.0 25.0

20.0 34.5 34.5

34.0 32.0

33.0 30.0 15.0

31.0 29.0 30.0 25.0 33.0 34.0 20.0 32.0

Winter

34.5 34.0 33.0 31.0 32.0 35.5

35.0 32.5 31.0 32.0 32.0 31.5

27.5 28.0 29.0 31.5 29.0 31.0

31.0 29.5 32.0 31.0

30.0 31.0 34.0 33.0 30.5 34.0 30.0

34.5 35.0

33.0 30.0 32.0 31.5

31.0 30.0 32.5 32.5 29.0 34.0 32.0 32.0 33.0 25.0 31.0 30.5 20.0 34.0 30.0 18.0

29.0 15.0 32.0 33.0 31.0 30.0 25.0 10.0 25.0 25.0 30.0 32.0 20.0 20.0 15.0 33.0 28.0 30.5 20.0 30.0 10.0 31.0 10.0

30.0

32.0 30.031.0

Summer 32.0

Figure 2·19. Winter and summer surface water salinity in the Arctic Ocean and adjacent seas (USSR Ministry of Defense 1980).

In general, surface water salinity in the Arctic Ocean and annual runoff of the Russian rivers is approximately 2100 km3 the adjacent shelf seas is relatively low compared to other (Aagaard and Carmack 1989). In the Canadian Arctic, the in- oceans (Figure 2·19). In the Arctic Ocean itself, surface sa- fluence of the Mackenzie River is evident during summer, linity varies between 30 and 33, and decreases in the area of when the salinity drops to 27 in the surface layer. Salinity in the shelf seas to below 30. In general, the salinity is lower the Arctic Basin increases with depth, reaching levels between during summer than winter due to input of freshwater from 32.5 and 34.5 at 100 m (USSR Ministry of Defense 1980). rivers and ice melt. Close to where the large Russian rivers A more detailed description of the hydrographic condi- enter the and the Siberian shelf, the salinity is below tions of the marine areas within the AMAP region is given 20 throughout the year and drops to as low as 10 during the in chapter 3, with more focus on vertical structure, mixing summer (USSR Ministry of Defense 1980). The average total processes and transport of water masses. Chapter 2 · Physical/Geographical Characteristics of the Arctic 23

Flaw leads or coastal polynyas occur at the landfast ice border where offshore winds separate the drift ice from the pack ice. Polynyas are open water regions that persist with- in closed sea ice cover, ranging in area up to thousands of Alaska C. square kilometers. These areas often have a high rate of pri- mary production of phytoplankton and are among the rich- T r a est marine areas in the world. They represent areas of high n s p o l energy exchange between ocean and atmosphere during the a r

D r winter months when the sea ice cover effectively prevents Beaufort i f Gyre t exchange between water and air. Permanent polynyas have been found near Cape Bathurst (Beaufort Sea), Baffin Bay, northeastern Greenland and a region extending east and

1 west of the northern part of the . Labrador C. East The two main ice circulation systems in the Arctic Basin Greenland C. are the clockwise Beaufort Gyre in the Amerasian Arctic, C. and the east to west Transpolar Drift in the Eurasian Arctic (Aagaard and Carmack 1989) (see Figure 3·23). Sea ice often circulates for more than five years in the Beaufort Gyre North Atlantic C. before being incorporated in the Transpolar Drift (Thorn- dike 1986, Rigor 1992). Most ice transported by the Trans- Atlantic currents polar Drift exits the central Arctic Basin through Fram Strait, Other currents 1 : West Spitsbergen Current Atlantic currents although some is lost through the Barents Sea. Transport Figure 2·20.Other currentsSurface ocean currents in the Arctic.1 : West Spitsbergen Current from the northern Kara Sea to Fram Strait may take as little as nine months, but averages two years (Rigor 1992, Pfir- man et al. 1997). 2.6.3. Ocean currents The annual and year-to-year distribution of pack ice is In a simplified picture, waters flowing north to the Arctic determined by temperature, winds, and ocean currents, such regions are comprised of warm currents originating from the as the Alaska Current, the Labrador Current, the East Green- Atlantic and Pacific Oceans, while cold currents flow out of land Current, the West Spitsbergen Current and the North the Arctic. Atlantic water enters the Arctic Ocean through Cape Current. Warm water transported north by the West Fram Strait and the Barents Sea, while Pacific water enters Spitsbergen and North Cape Currents cause embayments in via Bering Strait. Water leaves the Arctic largely via Fram the ice distribution in the Greenland and Barents Seas. The Strait, but also through the Canadian Arctic Archipelago North Cape Current also keeps the southern Barents Sea (Macdonald and Bewers 1996) (Figure 2·20). Most of the and the harbor of Murmansk free of ice during the winter. water in the Arctic Ocean originates from the Atlantic Ocean Sea ice is further discussed in chapter 3. (79%). The inflow through the Bering Strait is very modest (19%). The main water outflow is via the East Greenland Current (75%) and the outflow via the Canadian straits is Acknowledgments relatively small (25%). Inflow from rivers represents only Editor 2% and although this is a small percentage of the total, it is Janine L. Murray. much higher than in other oceans (Sugden 1982). For further detail about Arctic currents, refer to chapter 3. Authors Janine L. Murray, Louwrens Hacquebord, Dennis J. Gregor, Harald Loeng. 2.6.4. Sea ice Contributors Sea ice forms from ocean water and floats on its surface. It C.F. Forsberg, D.J. Henry, H. Jensson, J. Kämäri, M. Lange, forms when the temperature of the sea falls below the freez- R. Macdonald, E. Nikiforov, B. Njåstad, J.B. Ørebæk, ing point. The freezing point is dependent on the salinity of S. Pfirman, S. Pryamikov, O. Salvigsen, J.I. Solbakken, the seawater (–1.8°C for a salinity of 33) (Doherty and Kes- H. Welch, A. Zhulidov. ter 1974). The extent of ice cover changes with the , with an average maximum of 15 106 km2 in March and an average minimum of 8 106 km2 in September (Gloer- References sen et al. 1992) (see Figure 3·23). Aadlandsvik, B. and H. Loeng, 1991. A study of the climate system of the In the Arctic Basin, it is possible to distinguish three dif- Barents Sea. Polar Res. 10(1): 45-49. ferent areas of sea ice: the drifting pack ice, the marginal ice Aagaard, K. and E.C. Carmack, 1989. The role of sea ice and other freshwa- ter in the Arctic circulation. J. geophys. Res. 94: 485-498. zone and landfast ice. Perennial pack ice encompasses an AARI, 1985. Atlas arktiki (Atlas of the Arctic). Treshnikov, A.F. (ed.). Arctic area of approximately six million square kilometers. The and Antarctic Research Institute, State Committee of the USSR for Hy- drometeorology and Environmental Monitoring, Directorate-General for pack ice is broken up by leads, which vary from 1% open and of the USSR Council of Ministers, , water in winter to about 10-20% open water in summer 204p. (In Russian, English summaries). (Gow and Tucker 1990). The ice, which averages between Barry, R.G. and R.J. Chorley, 1992. Atmosphere, weather and climate. Rout- ledge, New York. 2.5-4 m in thickness, is intersected by pressure ridges which Barry, R.G. and F.K. Hare, 1974. Arctic climate. In: J.D. Ives and R.G. Barry are much thicker. The marginal ice zone is the region where (eds.). Arctic and alpine environments, pp. 17-54. Methuen, London. pack ice meets the open water. This area shifts with the sea- Barry, R.G. and J.D. Ives, 1974. Introduction. In: J.D. Ives and R.G. Barry (eds.). Arctic and alpine environments, pp. 1-13. Methuen, London. sons, and is often an area of high biological productivity. Bjerregaard, P., 1995. Health and environment in Greenland and other cir- Along the edges of many continents and archipelagoes, fast cumpolar areas. Sci. Total Environ. 160/161: 521-527. Bliss, L.C., 1981. North American and Scandinavian and polar des- ice develops each year and extends offshore. The edge of erts. In: L.C. Bliss, O.W. Heal and J.J. Moore (eds.). Tundra ecosystems: this landfast ice is found at an ocean depth of about 22 m. A comparitive analysis, pp. 8-24. Cambridge University Press, Cambridge. 24 AMAP Assessment Report

Bliss, L.C. and N.V. Matveyeva, 1992. Circumpolar Arctic vegetation. In: (eds.). Northern . Canadian perspectives, pp. 37-61. National F.S. Chapin III, R.L. Jeffries, J.F. Reynolds, G.R. Shaver, J. Svoboda and Hydrology Research Institute, Environment Canada, Saskatoon, NHRI E.W. Chu (eds.). Arctic ecosystems in a changing climate. An ecophysio- Science Report No. 1. logical perspective, pp. 59-89. Academic Press Inc., Toronto. Ministry for the Environment, 1992. Iceland, National Report to UNCED. CAFF, 1994. The state of protected areas in the circumpolar Arctic 1994. Skerpla, Reykjavik, 189p. Conservation of Arctic Flora and Fauna, Directorate for Nature Man- Moore, J.J., 1981. Mires. In: L.C. Bliss, O.W. Heal and J.J. Moore (eds.). agement, Trondheim, Habitat Conservation Report No. 1. Tundra ecosystems: A comparative analysis, pp. 35-37. Cambridge CAFF, 1996. Proposed protected areas in the circumpolar Arctic 1996. Con- University Press, Cambridge. servation of Arctis Flora and Fauna, Directorate for Nature National Wetlands Working Group, 1988. Wetlands of Canada. Sustainable Management, Trondheim, Habitat Conservation Report No. 2. Development Branch, Environment Canada, Ottawa, Ontario, and Poly- Doherty, B.T. and D.R. Kester, 1974. Freezing point of seawater. J. mar. Res. science Publications Inc., Montreal, Quebec, Ecological Land Classifica- 32(2): 285-300. tion Series No. 24, 452p. EEA (European Environment Agency), 1996. The state of the European Arctic Natural Resources Canada, 1994. Geology and Canada. Department of En- evironment. J.R. Hansen, R. Hansson and S. Norris (eds.). European Envi- ergy, Mines and Resources, Ottawa, 32p. ronment Agency, Copenhagen, EEA Environmental Monograph No. 3. NEFCO, 1995. Proposals for environmentally sound investment projects in Einarsson, M.A., 1984. . World survey of , Vol. the Russian part of the Barents Region. V. 1 Non-radioactive contamina- 15. Elsevier, Amsterdam. tion. AMAP Report. AMAP Secretariat, Oslo, 147p. Einarsson, T., 1980. Geology (in Icelandic). Mal og Menning, Reykjavik, 240p. NOAA, 1988. Data Announcement 88-MGG-02, Digital relief of the surface of Elíasson, J., 1994. Northern hydrology in Iceland. In: T.D. Prowse, C.S.L. the Earth. NOAA, National Geophysical Data Center, Boulder, Colorado. Ommaney and L.E. Watson (eds.). Northern hydrology: International Nordic Council of Ministers, 1996. The Nordic Arctic Environment – Unspoilt, perspectives, pp. 41-80. Environment Canada, Saskatoon, Saskatche- Exploited, Polluted? Nordic Council of Ministers, Copenhagen. Nord wan, NHRI Science Report No. 3. 1996:26. 240p. Encyclopedia Britannica, 1990. The New Encyclopedia Britannica, Chicago. Parkinson, C.L., J.C. Comiso, H.J. Zwally, D.J. Cavalieri, P. Gloersen and W.J. Vol. 14, pp. 288-292. Campbell, 1987. Arctic sea ice, 1973-1976: Satellite passive-microwave ob- Environmental Defense Fund, 1996. Surface ocean currents. Environmental servations. Scientific and Technical Information Branch, National Aeronau- Defense Fund, New York. (1 map) tics and Space Administration, Washington D.C., NASA SP-489, pp. 32-33. European Climate Support Network and National Meteorological Services, Pfirman, S.L., J. Koegler and B. Anselme, 1995. Coastal environments of the 1995. Climate of Europe. Recent variations, present state and future western Kara and eastern Barents Seas. Deep-Sea Res. 42(6): 1391-1412. prospects. 72p. Pfirman, S.L., J.W. Koegler and I. Rigor, 1997. Potential for rapid transport Everett, K.R., V.D. Vassiljevskaya, J. Brown and B.D. Walker, 1981. Tundra of contaminants from the Kara Sea. Sci. Total Environ. 202: 111-122. and analogous soils. In: L.C. Bliss, O.W. Heal and J.J. Moore (eds.). Plancenter Ltd., 1991. Synthesis report. Environmental Priority Action Pro- Tundra ecosystems: A comparative analysis, pp. 139-179. Cambridge gramme for Leningrad, Leningrad Region, Karelia and . Plan- University Press, Cambridge. center Ltd., IVO International Vesi-Hydro Consulting Ltd., Enviro Data French, H.M. and O. Slaymaker, 1993. Canada’s cold environments. Mc- Ltd., Outukumpu EcoEnergy Ltd., September 1991, 191p. Gill-Queen’s University Press, Montreal and Kingston. Pritchard, D.W., 1967. Observations of circulation in coastal plain estuaries. Geological Survey of Canada, 1995. Generalized geological map of the In: G.H. Lauff (ed.). Estuaries. Am. Ass. Adv. Sci. Publs Vol. 83: 37-44. world, and linked databases. Open File 2915d. Prik, Z.M., 1959. Mean position of surface pressure and temperature distribution Gloersen, P., W.J. Campbell, D.J. Cavalieri, J.C. Comiso, C.L. Parkinson in the Arctic. Tr. Arkticheskogo Nauch.-Issled. Inst. 217: 5-34. (In Russian). and H.J. Zwally, 1992. Arctic and Antarctic sea ice, 1978-1987: Satellite Prowse, T.D., 1990. Northern hydrology: an overview. In: T.D. Prowse and C.S.L. passive microwave observations and analysis. National Aeronautics and Ommanney (eds.). Northern hydrology: Canadian perspectives, pp. 1-36. En- Space Administration, Washington D.C., NASA SP511. vironment Canada, Saskatoon, Saskatchewan, NHRI Science Report No. 1. Gordeev, V.V. and I.S. Sidorov, 1993. Concentrations of major elements and Rieger, S., 1974. Arctic soils. Pp. 749-769 In: J.D. Ives and R.G. Barry (eds.). their outflow into the by the Lena River. Mar. Chem. 43: 33-46. Arctic and alpine environments. Methuen and Co. Ltd., London. Gow, A.J. and W.B. Tucker III, 1990. Sea ice in the polar regions. In: W.O. Ries, T., 1994. The Republic of Karelia. The first years after the USSR: some Smith (ed.). Polar , Part A: Physical science, pp. 47-117. basic data. Report from the Norwegian Foreign Department, Oslo, 86p. Academic Press Inc., San Diego. Rigor, I., 1992. Arctic Ocean buoy program. ARCOS Newsletter 44: 1-3. Grigoriev, V.Y. and B.L. Sokolov, 1994. Northern hydrology in the Former Rust, B.R. and J.P. Coakley, 1970. Physico-chemical characteristics and post- Soviet Union (FSU). In: T.D. Prowse, C.S.L. Ommaney and L.E. Watson glacial desalination of Stanwell-Fletcher Lake, Arctic Canada. Can. J. (eds.). Northern hydrology: International perspectives, pp. 147-179. Envi- Earth Sci. 7: 900-911. ronment Canada, Saskatoon, Saskatchewan, NHRI Science Report No. 3. Rydén, B.E., 1981. Hydrology of northern tundra. In: L.C. Bliss, O.W. Heal Hardisty, P., V. Schilder, T. Dabrowski and J. Wells, 1991. Yukon and and J.J. Moore (eds.). Tundra ecosystems: A comparative analysis, pp. groundwater database. In: T.D. Prowse, C.S.L. 115-137. Cambridge University Press, Cambridge. Ommaney and L.E. Watson (eds.). Northern hydrology: International Schindler, D.W., H.E. Welch, J. Kalff, G. Brunskill and N. Kritsch, 1974. perspectives, pp. 465-482. Environment Canada, Saskatoon, Saskatche- Physical and chemical of Char Lake, Cornwallis Island (75°N wan, NHRI Science Report No. 3. Lat.). J. Fish. Res. Bd Can. 31: 585-662. Ikeda, M., 1990a. Decadal oscillation of the air-sea-ocean system in the SCOR, 1979. The Arctic Ocean heat budget. University of Bergen, Geophys- . Atmosphere-Ocean 28: 106-139. ical Institute, Norway, Working Group 58, Report No. 52, 98p. Ikeda, M., 1990b. Feedback mechanism among decadal oscillations in the Sly, P.G., 1995. Human impacts on the Hudson Bay region: present and northern hemisphere atmospheric circulation, sea ice and ocean circula- future environmental concerns. In: M. Munawar and M. Luotola (eds.). tion. Ann. Glaciol. 14: 120-123. The contaminants in the Nordic ecosystem: Dynamics, processes and fate, Ives, J.D., 1974. Permafrost. In: J.D. Ives and R.G. Barry (eds.). Arctic and pp. 171-263. SPB Academic Publishing, Amsterdam. alpine environments, pp. 159-194. Methuen and Co. Ltd., London. Stonehouse, B., 1989. Polar . Blackie, London, 222p. Keltikangas, M., J. Laine, P. Puttonen and K. Seppala, 1986. Vuosina 1930- Sugden, D., 1982. Arctic and Antarctic; A modern geographical synthesis. 1978 ojitetut suot: Ojitusalueiden inventoinnin tuloksia. Acta Forestalia Basil Blackwell, Oxford. Fennica 193. (In Finnish). Thorndike, A.F., 1986. Kinematics of sea ice. In: N. Untersteiner (ed.). Geo- Killingtveit, Å. and K. Sand, 1991. On aerial distribution of snowcover in a physics of sea ice, pp. 489-550. Plenum Press, New York, NATO Ad- mountainous area. In: T.D. Prowse and C.S.L. Ommanney (eds.). Northern vanced Studies Institute Series B, Physics 146. hydrology: Selected perspectives, Proceedings of the Northern Hydrology USSR Ministry of Defense, 1980. The Atlas of the Oceans - Arctic Ocean. Symposium, 10-12 July, 1990, Saskatoon, Saskatchewan, pp. 189-203. USSR Ministry of Defense. Environment Canada, Saskatoon, Saskatchewan, NHRI Symposium No. 6. van Everdingen, R.O., 1990. Groundwater hydrology. In: T.D. Prowse and Landsberg, H.E. (ed.), 1970. World survey of climatology. Vol. 14. Elsevier, C.S.L. Ommanney (eds.). Northern hydrology. Canadian perspectives, pp. Amsterdam. 77-101. National Hydrology Research Institute, Environment Canada, Larsen, J.A., 1973. Plant communities north of the forest border, Keewatin, Saskatoon, NHRI Science Report No. 1. Northwest Territories. Can. Field-Nat. 87: 241-248. Varjo, U. and W. Tietze (eds.), 1987. Norden. Man and environment. Gebr. Lauff, G.H. (ed.), 1967. Estuaries. American Association for the Advance- Borntraeger, Berlin, Stuttgart. ment of Science, Washington D.C., 757p. Vinje, T.E., 1976. Sea ice conditions in the European sector of the marginal Linell, K.A. and J.C.F. Tedrow, 1981. Soil and permafrost surveys in the seas of the Arctic, 1966-1975. Norsk Polarinst. Årbok, 1975: 163-174. Arctic. Clarendon Press, Oxford, 279p. Washburn, A.L., 1979. Geocryology. A survey of periglacial processes and Loshchicov, V.S, 1965. Snow cover on the ice of the central Arctic. Probl. environments. Edward Arnold Ltd., London, 406p. Arktiki 17: 36-45. (In Russian). Welch, H.E, 1991. Comparisons between lakes and seas during the Arctic Luzin, G.P., M. Pretes and V.V. Vasiliev, 1994. The Kola Peninsula: geogra- winter. Arct. alp. Res. 23: 11-23. phy, history and resources. Arctic 47: 1-15. Welch, H.E. and J.A. Legault, 1986. Precipitation chemistry and chemical lim- Macdonald, R.W. and J.M. Bewers, 1996. Contaminants in the Arctic marine nology of fertilized and natural lakes at Saqvaqjuac, NWT. Can. J. Fish. environment: priorities for protection. ICES J. mar. Sci. 53: 537-563. aquat. Sci. 43: 1104-1134. Macdonald, R.W., D.W. Paton, E.C. Carmack and A. Omstedt, 1995. The Welch, H.E., J.A. Legault and M.A. Bergmann, 1987. Effects of snow and ice freshwater budget and under-ice spreading of Mackenzie River water in on the annual cycles of heat and light in Saqvaqjuac lakes. Can. J. Fish. the Canadian Beaufort Sea based on salinity and 18O/16O measurements aquat. Sci. 44: 1451-1461. in water and ice. J. geophys. Res. 100(C1): 895-919. Woo, M.K., 1992. Arctic streamflow. In: M.K. Woo and D.J. Gregor (eds.). Mackay, D.K. and O.H. Løken, 1974. Arctic hydrology. In: J.D. Ives and Arctic environment: Past, present and future, pp. 105-111. McMaster R.G. Barry (eds.). Arctic and alpine environments, pp. 111-132. Meth- University, Department of Geography, Hamilton. uen and Co. Ltd., London. Woo, M.K. and D.J. Gregor, 1992. Arctic environment: Past, present and Marsh, P., 1990. Snow hydrology. In: T.D. Prowse and C.S.L. Ommanney future. McMaster University, Department of Geography, Hamilton, 164p.